610 / 2019-04-23 13:15:46

Transcriptional network regulation of the brassinosteroid signaling pathway by the BES1-TPL-HDA19 co-repressor complex

Brassinosteroids, Plant hormone, Histone deacetylase, Gene network, RNA-seq

全体主题 > Hormones

Brassinosteroids (BR) are plant steroid hormones that are essential for diverse growth and developmental processes across the whole life cycle of plants. In Arabidopsis thaliana, the BR-related transcription factors BES1 and BZR1 regulate a range of global gene expression in response to BR and several external signaling cues; however, the molecular mechanisms by which they mediate the reprograming of downstream transcription remain unclear. We here report that formation of a protein complex between BES1/BZR1 and Histone Deacetylase 19 (HDA19) via the conserved ERF-associated amphiphilic repression (EAR) motif proved essential for regulation of BR signaling-related gene expression. Defects in BR-related functions of BES1 and BZR1 proteins containing a mutated EAR motif were completely rescued by artificial fusion with SRDX, TOPLESS (TPL), or HDA19 proteins. RNA-sequencing analysis of Arabidopsis plants over-expressing bes1-DmEAR or bes1-DmEAR-HDA19 revealed an essential role for HDA19 activity in regulation of BES1/BZR1-mediated BR signaling. In addition to BR-related gene expression, the BES1-HDA19 transcription factor complex was important for abiotic stress-related drought stress tolerance and organ boundary formation. These results suggested that integrating activation of BR signaling pathways with the formation of the protein complex containing BES1/BZR1 and TPL-HDA19 via the EAR motif was important in fine-tuning BR-related gene networks in plants.